In the coming year it is anticipated that a major portion of research time will be allocated to the direction of a program project grant designed to study different types of cochlear implants. Other responsibilities will include principal investigator of the patient management portion of the grant and participation in the electrophysiologic project. The electrophysiologic project is designed to produce an animal model of auditory nerve ganglion cell loss and determine if characteristic brainstem evoked responses appear. The study is aimed at developing a preoperative test that will predict residual auditory nerve survival. The bone resorption in chronic ear disease project will focus on studying Langerhans cells in a guinea pig cholesteatoma model. A monoclonal antibody to guinea pig Langerhans cells is being produced in our laboratory. This marker will be used to identify these cells during cholesteatoma formation and determine their activity during bone resorption at the light and electron microscopic levels.